Rapid and visual detection of soybean mosaic virus SC7 with a loop-mediated isothermal amplification strategy

Soybean mosaic virus (SMV) is the most prevalent viral pathogen of soybean worldwide that reduces seed quality and causes serious losses in yields. The accurate, rapid and early detection of SMV strains is crucial for screening SMV-resistant soybean varieties and controlling soybean mosaic disease timely. In this study, we report a loop-mediated isothermal amplification (LAMP) assay for visual and rapid detection of SMV-SC7, the major prevalent SMV strain in China, in soybean leaves. Specific primers were rationally designed and tested to detect the SMV-SC7 strain. The detection limit for SMV-SC7 can be as low as 10−4 ng/μL by the developed LAMP assay. These results were visualized by three indicators (SYBR green I, neutral red and hydroxy naphthol blue) with high fidelity. The high analytical performance of the LAMP assay was demonstrated with 21 soybean cultivars, among which 8 soybean cultivars were further inoculated with consistent results to those achieved by LAMP. This visual and rapid LAMP assay is highly promising for early detection of SMV-SC7-associated plant diseases.